Stormorken syndrome is a multiorgan hereditary disease caused by dysfunction of the endoplasmic reticulum (ER) Ca2+ sensor protein STIM1, which forms the Ca2+ release-activated Ca2+ (CRAC) channel together with the plasma membrane channel Orai1. ER Ca2+ store depletion activates STIM1 by releasing the intramolecular "clamp" formed between the coiled coil 1 (CC1) and CC3 domains of the protein, enabling the C terminus to extend and interact with Orai1. The most frequently occurring mutation in patients with Stormorken syndrome is R304W, which destabilizes and extends the STIM1 C terminus independently of ER Ca2+ store depletion, causing constitutive binding to Orai1 and CRAC channel activation. We found that in cis deletion of one amino acid residue, Glu296 (which we called E296del) reversed the pathological effects of R304W. Homozygous Stim1 E296del+R304W mice were viable and phenotypically indistinguishable from wild-type mice. NMR spectroscopy, molecular dynamics simulations, and cellular experiments revealed that although the R304W mutation prevented CC1 from interacting with CC3, the additional deletion of Glu296 opposed this effect by enabling CC1-CC3 binding and restoring the CC domain interactions within STIM1 that are critical for proper CRAC channel function. Our results provide insight into the activation mechanism of STIM1 by clarifying the molecular basis of mutation-elicited protein dysfunction and pathophysiology.
- MeSH
- aminokyseliny metabolismus MeSH
- endoplazmatické retikulum metabolismus MeSH
- kanály aktivované uvolněním vápníku * genetika MeSH
- membránové proteiny * metabolismus MeSH
- mutace MeSH
- myši MeSH
- protein ORAI1 metabolismus MeSH
- protein STIM1 genetika MeSH
- vápník metabolismus MeSH
- vápníkové kanály metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The calcium release activated calcium channel is activated by the endoplasmic reticulum-resident calcium sensor protein STIM1. On activation, STIM1 C terminus changes from an inactive, tight to an active, extended conformation. A coiled-coil clamp involving the CC1 and CC3 domains is essential in controlling STIM1 activation, with CC1 as the key entity. The nuclear magnetic resonance-derived solution structure of the CC1 domain represents a three-helix bundle stabilized by interhelical contacts, which are absent in the Stormorken disease-related STIM1 R304W mutant. Two interhelical sites between the CC1α1 and CC1α2 helices are key in controlling STIM1 activation, affecting the balance between tight and extended conformations. Nuclear magnetic resonance-directed mutations within these interhelical interactions restore the physiological, store-dependent activation behavior of the gain-of-function STIM1 R304W mutant. This study reveals the functional impact of interhelical interactions within the CC1 domain for modifying the CC1-CC3 clamp strength to control the activation of STIM1.
- MeSH
- abnormální erytrocyty MeSH
- dyslexie genetika MeSH
- HEK293 buňky MeSH
- ichtyóza genetika MeSH
- kanály aktivované uvolněním vápníku metabolismus MeSH
- klonování DNA MeSH
- konformace nukleové kyseliny MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- metoda terčíkového zámku MeSH
- migréna genetika MeSH
- mióza genetika MeSH
- molekulární modely MeSH
- mutace genetika MeSH
- nádorové proteiny genetika MeSH
- protein ORAI1 genetika MeSH
- protein STIM1 genetika MeSH
- slezina abnormality MeSH
- svalová únava genetika MeSH
- trombocytopatie genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
INTRODUCTION: Epidermolysis bullosa (EB) describes a family of rare genetic blistering skin disorders. Various subtypes are clinically and genetically heterogeneous, and a lethal postpartum form of EB is the generalized severe junctional EB (gs-JEB). gs-JEB is mainly caused by premature termination codon (PTC) mutations in the skin anchor protein LAMB3 (laminin subunit beta-3) gene. The ribosome in majority of translational reads of LAMB3PTC mRNA aborts protein synthesis at the PTC signal, with production of a truncated, nonfunctional protein. This leaves an endogenous readthrough mechanism needed for production of functional full-length Lamb3 protein albeit at insufficient levels. Here, we report on the development of drugs targeting ribosomal protein L35 (rpL35), a ribosomal modifier for customized increase in production of full-length Lamb3 protein from a LAMB3PTC mRNA. METHODS: Molecular docking studies were employed to identify small molecules binding to human rpL35. Molecular determinants of small molecule binding to rpL35 were further characterized by titration of the protein with these ligands as monitored by nuclear magnetic resonance (NMR) spectroscopy in solution. Changes in NMR chemical shifts were used to map the docking sites for small molecules onto the 3D structure of the rpL35. RESULTS: Molecular docking studies identified 2 FDA-approved drugs, atazanavir and artesunate, as candidate small-molecule binders of rpL35. Molecular interaction studies predicted several binding clusters for both compounds scattered throughout the rpL35 structure. NMR titration studies identified the amino acids participating in the ligand interaction. Combining docking predictions for atazanavir and artesunate with rpL35 and NMR analysis of rpL35 ligand interaction, one binding cluster located near the N-terminus of rpL35 was identified. In this region, the nonidentical binding sites for atazanavir and artesunate overlap and are accessible when rpL35 is integrated in its natural ribosomal environment. CONCLUSION: Atazanavir and artesunate were identified as candidate compounds binding to ribosomal protein rpL35 and may now be tested for their potential to trigger a rpL35 ribosomal switch to increase production of full-length Lamb3 protein from a LAMB3PTC mRNA for targeted systemic therapy in treating gs-JEB.
- MeSH
- artesunát chemie MeSH
- atazanavir sulfát chemie MeSH
- epidermolysis bullosa junkční genetika patologie MeSH
- fyziologie kůže MeSH
- kůže patologie MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- molekuly buněčné adheze genetika MeSH
- ribozomální proteiny metabolismus MeSH
- simulace molekulového dockingu MeSH
- vazba proteinů fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
We report a new NMR-scale purification procedure for two recombinant wild type fragments of the stromal interaction molecule 1 (STIM1). This protein acts as a calcium sensor in the endoplasmic reticulum (ER) and extends into the cytosol accumulating at ER - plasma membrane (PM) junctions upon calcium store depletion ultimately leading to activation of the Orai/CRAC channel. The functionally relevant cytosolic part of STIM1 consists of three coiled coil domains, which are mainly involved in intra- and inter-molecular homomeric interactions as well as coupling to and gating of CRAC channels. The optimized one-step rapid purification procedure for two 15N,13C isotope-labeled cytosolic coiled coil fragments, which avoids the problems of previous approaches. The high yields of soluble well folded 15N,13C isotope-labeled cytosolic coiled coil fragments followed by detergent screening provide for initial NMR characterization of these domains. The longer 30.5 kDa fragment represents the largest STIM1 wild type fragment that has been recombinantly prepared and characterized in solution without need for mutation or refolding.
- MeSH
- chromatografie afinitní MeSH
- dynamický rozptyl světla MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- izotopové značení MeSH
- izotopy dusíku chemie izolace a purifikace MeSH
- izotopy uhlíku chemie izolace a purifikace MeSH
- lidé MeSH
- nádorové proteiny chemie izolace a purifikace MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- protein STIM1 chemie izolace a purifikace MeSH
- proteinové domény MeSH
- rekombinantní proteiny chemie izolace a purifikace MeSH
- rozpustnost MeSH
- sbalování proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
STIM1 and Orai1 are key components of the Ca2+-release activated Ca2+ (CRAC) current. Orai1, which represents the subunit forming the CRAC channel complex, is activated by the ER resident Ca2+ sensor STIM1. The genetically inherited Stormorken syndrome disease has been associated with the STIM1 single point R304W mutant. The resulting constitutive activation of Orai1 mainly involves the CRAC-activating domain CAD/SOAR of STIM1, the exposure of which is regulated by the molecular interplay between three cytosolic STIM1 coiled-coil (CC) domains. Here we present a dual mechanism by which STIM1 R304W attains the pathophysiological, constitutive activity eliciting the Stormorken syndrome. The R304W mutation induces a helical elongation within the CC1 domain, which together with an increased CC1 homomerization, destabilize the resting state of STIM1. This culminates, even in the absence of store depletion, in structural extension and CAD/SOAR exposure of STIM1 R304W leading to constitutive CRAC channel activation and Stormorken disease.
- MeSH
- abnormální erytrocyty metabolismus patologie MeSH
- bakteriální proteiny genetika metabolismus MeSH
- bodová mutace * MeSH
- dyslexie genetika metabolismus patologie MeSH
- exprese genu MeSH
- HEK293 buňky MeSH
- ichtyóza genetika metabolismus patologie MeSH
- interakční proteinové domény a motivy MeSH
- iontový transport MeSH
- konformace proteinů, alfa-helix MeSH
- lidé MeSH
- luminescentní proteiny genetika metabolismus MeSH
- metoda terčíkového zámku MeSH
- migréna genetika metabolismus patologie MeSH
- mióza genetika metabolismus patologie MeSH
- molekulární modely MeSH
- multimerizace proteinu MeSH
- nádorové proteiny chemie genetika metabolismus MeSH
- protein ORAI1 chemie genetika metabolismus MeSH
- protein STIM1 chemie genetika metabolismus MeSH
- regulace genové exprese MeSH
- rekombinantní proteiny chemie genetika metabolismus MeSH
- reportérové geny MeSH
- sekvence aminokyselin MeSH
- slezina abnormality metabolismus patologie MeSH
- substituce aminokyselin MeSH
- svalová únava genetika MeSH
- trombocytopatie genetika metabolismus patologie MeSH
- vápník chemie metabolismus MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- zelené fluorescenční proteiny genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The extrinsic proteins of photosystem II of higher plants and green algae PsbO, PsbP, PsbQ, and PsbR are essential for stable oxygen production in the oxygen evolving center. In the available X-ray crystallographic structure of higher plant PsbQ residues S14-Y33 are missing. Building on the backbone NMR assignment of PsbQ, which includes this "missing link", we report the extended resonance assignment including side chain atoms. Based on nuclear Overhauser effect spectra a high resolution solution structure of PsbQ with a backbone RMSD of 0.81 Å was obtained from torsion angle dynamics. Within the N-terminal residues 1-45 the solution structure deviates significantly from the X-ray crystallographic one, while the four-helix bundle core found previously is confirmed. A short α-helix is observed in the solution structure at the location where a β-strand had been proposed in the earlier crystallographic study. NMR relaxation data and unrestrained molecular dynamics simulations corroborate that the N-terminal region behaves as a flexible tail with a persistent short local helical secondary structure, while no indications of forming a β-strand are found.
- MeSH
- fotosystém II - proteinový komplex chemie genetika metabolismus MeSH
- krystalografie rentgenová MeSH
- magnetická rezonanční spektroskopie metody MeSH
- rekombinantní proteiny chemie metabolismus MeSH
- rostlinné proteiny chemie genetika metabolismus MeSH
- roztoky MeSH
- sekundární struktura proteinů * MeSH
- sekvence aminokyselin MeSH
- simulace molekulární dynamiky * MeSH
- Spinacia oleracea genetika metabolismus MeSH
- terciární struktura proteinů MeSH
- termodynamika MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PsbP (23 kDa) is an extrinsic eukaryotic protein of photosystem II found in the thylakoid membrane of higher plants and green algae. It has been proven to be indispensable for proper functioning of the oxygen evolving complex. By interaction with other extrinsic proteins (PsbQ, PsbO and PsbR), it modulates the concentration of two cofactors of the water splitting reaction, Ca(2+) and Cl(-). The crystallographic structure of PsbP from Spinacia oleracea lacks the N-terminal part as well as two inner regions which were modelled as loops. Those unresolved parts are believed to be functionally crucial for the binding of PsbP to the thylakoid membrane. In this NMR study we report (1)H, (15)N and (13)C resonance assignments of the backbone and side chain atoms of the PsbP protein. Based on these data, an estimate of the secondary structure has been made. The structural motifs found fit the resolved parts of the crystallographic structure very well. In addition, the complete assignment set provides preliminary insight into the dynamic regions.
- MeSH
- fotosystém II - proteinový komplex chemie MeSH
- krystalografie rentgenová MeSH
- molekulární sekvence - údaje MeSH
- protonová magnetická rezonanční spektroskopie * MeSH
- rostlinné proteiny chemie MeSH
- sekundární struktura proteinů MeSH
- sekvence aminokyselin MeSH
- Spinacia oleracea chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
